cheever



(No Model.) 2Sheets-Sheet 1.

" A. GMHOLG'OMBE & O. A. GHEEVER.

Electrical Rock Drill. -No. 235,948. Patented Dem-28,1880.

J71 var: Z1775.

(No Model.) 2 Sheets-Sheet 2. A. G. HOLOOMBE &,G. -A. GHEEVER.

Electrical Rock Drill.

Patented Dec. 28,1880.

W'hwsmeg f-U ED ATE- PATENT OF IC r -E e. HoLcoMBE, 1on1 GRANBY, coNu,AND cHARLEs A. OHEEVER, or IKEWYORK, n Y.,-ASSI GNORS'TO SAID CHARLES A.CHEEVER, TRUSTEE.

ELECTRICAL ROCK-DRILL.

- srEcmIcA'rioN forming part bf Letters Patent No. 235,948 datedDecember 28, 1880..

- Be it known that we, ALFRED G. Hoh- COMBE, of Granby, inthe county ofHartford 1 and State of Connecticut, and CHARLES A.-

5 CHEEVER, of the city, county,- and State of New York, both citizens ofthe United States,

jointly have invented certainnew and useful Improvements inElectriclIDrills, of which the following is a specification..-

. actuatedb'y electro-magnetismr Its object is to secure a simple,efli'cient, and durable ma chine, which .ends we attain-by certain novelcombinations'and organizations of old instru- 5 mentalities, designatedby'the' claims at the end of this specification.- I

- Inthe accompanying drawings, Figure 1 re p resents a longitudinalcentral sect-ionthrongh an elect-ricdi'ill embracingourir'n'proveinents.

Fig. 2 is a plan View ofthe same, Fig. 3 showsa'" plan view, and Fig. 4avertical central section -jthro'ugh a device by whichthe drilling-toolmay be retracted. Fig. 5 representsa side elevation of a rheotome orcircuit-breaker for regulating the speed of the drill. Fig, 6 is a.diagram showing one methodof organizing f t-heapparatus, and'Fig. 7represents amodifiedformof' the drill. Theapparatus shownin Figs. 3, 4,and 7 is not claimed here, as it 7 3o constitutes the subject-matter ofa division of this application filed by us July 39, 1880, serial No.14,531. A

The mechanism is shown as mounted in a' "skeleton-frame consisting oftwo heads orcast- 3'5 ings, a'a', united by rods b. The lower orforward". head or, casting is provided with sockets,in'which-areinserted longitudinallyadj ustablelegs c, constituting a;base or tripod,

upon which the mechanism is supported and 0 by means of which it may beadjustedat the 1 V proper angle relatively to its work, 7 4 A coilor'helix, d, of properly -"ins'ulated';.

, wire, constituting an ordina eleetro-magnet, is mounted in a slidingstoc or frame (shown 5 "as consisting of head-pieces c e: having thecapacity of sliding upon the rods ,and united by suitable rods, d. Ascrew-rod, 'm,tu1'ning in suitable bearings' in the frame, is providedwith a crank-handle or winch, m",--by which to turn it when desired. Thescrew of this Application filed Hay -Our invention relates to drills ofthe class gthelower plate or' casting, e, and through 28, 188i). (Nomodel.)

spindle works ina corresponding screw in a spur-wheel, Z, whichturnsin-suitable bearings in the head e of the sliding stock or frame,by which means the st 0ck can be moved longitudinally in eitherdirection desired, The wheel I is normally prevented from turningbackward by a spring-pawl, m taking into ratchet-teeth therein or othersuitable locking device. I

An ordinary soft-iron core, f, has the capacity of sliding freelyendwise through the center-of the coil-or helix, as-usual in instruments"of this class.- A rod, f, constituting .an axial extension of the core,passes through I 5 suitable guides in a box or bracket, e secured tosaid casting. ,A spiral spring encircles .this rod, and bears at one endagainst the bracket and at the other against the screw-. nut g on the"rod. By thismeans the resili-. ence of the spring may be adjusted untilit is sufficient to act as acounterpoise to the weight of the'core andits'appurtenances,so as normally to hold the parts in the positionshown. in Fig. lthat is, ina retracted position-in which position. itwill be seen a portion of the core projects beyond the coillA'drilling-tool is secured to the rod-f' by suitable well-known means. Apolygonal rod, f constituting an axialextension of the core, passesaxially through a gear-Wheel, i, turning in suitable bearings in thehead6. This polygonal rod has the capacity of sliding freely endwise throughthe spur-wheel, the two, howevn being compelled to turn together. Thisspur-wheel tgears with the spur-wheel Z, hereinbefore referred to.

The head j on the-rod f? on each backstroke. acts on an adjustable stud,wiper, or plug fitted on-.a lever, 70, rocking on asuitable pivot orrock-shattk', on the frame. A pawl carried by this lever acts on aseries of ratchet-teeth on the-face of the wheel 1 and thusimparts to itan intermittent rotary move ment in a well-known way. The feed-pawl isretracted at each stroke by a suitable recoilspring on its rock-shaft.The distance which the rod is carried at'each stroke of the drill, andconsequently the feed of the drill, is regu lated partly by the distancethe plug projects from the rocking lever and partly by the length of thestroke .of the drill itself. The

parts are so proportioned that the normal feed imparted to the drill isequal to the distance which it would penetrate the softest substanceupon which it is designed to operate. Should from any cause the drillnot penetrate its full distance, the conical point of the rod f wouldprevent the pawl from feeding its full distance until the next stroke,or until the drill had penetrated to the desired depth, when the fullfeed would be resumed. This automatic correlation of parts prevents thestraining or breaking of the ap paratus. It will, of course," beunderstood that the wheel 2' gears into the wheel Z and revolves it. Asthe screw m is normally .locked from turning, the frame is necessarilyfedforward by the turning of the wheel on its screwed spindle. By thismeans our improved drill has imparted to it the capacity of beingautomatically fed forward by the revolution of the screw-wheel Z on thescrew,- and of being retracted by' the revolution of the screw-spindle min the screw-wheel, while the latter is prevented from turning.

Under the organizationabove described it will be seen that thedrillingtool is partially rotated automatically on each back-stroke.Instead of the polygonal shatt-and-ratchet arrangement above describedfor producing this result, it might be accomplished by a curved slot orgroove on the rod f in which a spline on the feed-wheel works in awellknown way. Figs. 3 and a represent a device by which theadjustability of the stock, after completing its forward movement, mayinstantaneously be retracted to its starting-point. This end .isattained by making the hole through the wheel 1 large enough to enableit to slide freely on the feed-screw m, and providing two half-nuts,

n, sliding in guides on the face of the wheel 1-,

their movements beingcontrolled by pins on a ring, 0, fitting in thehalf-nuts, so that they embrace the screwwhen the ring is in properpositionthat is, in the position shown in Fig. 3-in which position theyare held by a pawl,

o The half-nuts are released from the screw by releasing the pawl andturning the ring.

backward, 'which allows the wheel Z to slide freely on the screw and thestock to slide freely in its bearing. This last-described device isapplieableto drills working in horizontal or inclined rather than invertical positions,unless the drills have their moving partssulficiently light to be readily lifted. The drill is thrust forward todo its work by electro-magnetism, the electric current being derivedfrom a suita le generator in a well-known way. Fig. 6 represents oneorganization of the apparatus to] accomplishing this result. The coil orhelix is shown as included in an electric circuit in which is alsoincluded a suitable generator of electricity, such as adynamoelectric ormagneto-electric machine, and a rheotome 0r circuit-breaker, s.

Fig. 1 represents the parts in their normal position'ready to beginwork. The passage of an electric current through the coil'or helix.

C draws the core f forward, driving the drill against the surface to beperforated. Asthe drill completes its stroke the circuit is broken, andthe core and tool are retracted by the ac- .tionof thecounterbalancing-spring g. The

operation above described'is then repeated, by which means the drill maybe driven with any desired degree of rapidity. The operation abovedescribed may be reversed in well known ways, so as to cause the core tocomg press an actuating-spring on its back-stroke, the forward thrust ofthe-drill being given by the recoil of the spring. r

Fig. 5 shows an adjustable rheotome or circuit-breaker, by means ofwhich the rapidity of the stroke may be varied; but other wellknownforms of circuit-breakers might be enrployed instead.

An elbow-leveigpp rocking on a pivot, p, is provided with an adjustableweight, g, capable of sliding endwise on the arm 19 of the elbow-lever,and provided with a set-screw or other locking device to secure it thedesired distance from the pivot. The arm 13 constitutes or carries thearmature of an ordinary horseshoe electro-magnet, a, the coils of which.

are connected with circuit wires or conductors a Under the organizationshown the current passes along the wire r to the pivot p, v

and along the arm p by the contact-screw r, to the helices oftheelectro-magnct r, and from thence, by the conductor 7 to the helix ofthe drill, and back to the generator. \Vhen the current passes, theelectro-magnet r attracts the armature p untilit strikes the arm 1' thusbreaking the contact between the arm 11 and the screw 9", and throwingthe rod 1) and weight g into its rearmost position, the resilience ofthe arm allowingit to bend according to the position of the weight g.The reaction of this spring throws the armature down again, closing thecontact at 7", and allowing the current to pass through the helix of thedrill again. theduration of the passage of the current being governed bythe resilience of the rod 10 and the position of the weight thereon.

The weight, moreover, causes the rod to act as 'a pendulum, andconsequently regulates the number of pulsations allowed to pass in agiven time. The rod 19 mightbe marked with the number of vibrationsincident to. a given adjustment of the-weight, so as to admit of itsbeing readily adjusted to the desired'number of strokes. The rheotome isinclosed, in a box or. casing to protect itfrom dust' or injury.

Two drills might be operated from one rheotome constructed on thisprinciple, by forming another circuit through the stop '1 as shown bythe dotted line 1 inwhich circuit a second drill is placed. Thereturn-conductor from this second drill would in this case pass directlyto the generator, or join the returnconductor of the first drill.Underthis arof drills the generator is sufficiently powerful ratus, inwhich the drill is set forth, of the I therein, the coil or helixmounted in the stock,

rangement thetwodrills would be alternately operated, one when thearmature of the lever p is in contact with the screw'r, and the otherwhen it is in contact with the stop T The rheotome might be placed. nearthe generator, if desired, or be placed near the drill,

so as to be readily adjusted by the attendant; or th'erheotome might bemounted directly upon the drill itself.

In Fig. 6 the generator is shown as consisting of a dynamo-electric ormagneto-electric machine, 3, connected by a conductor or circuit-wire,r, to the rheotome s, which is, in turn, connected with the helix of thedrill by the conductor 4', the circuit being completed from the drill tothe generator by the conductor r. in circuit; but it is evident that anynumber to operate may be placed in circuit.

\ In Fig. 6 a shunt-wire or short circuit, T is shown as connecting thegenerator and. rheotome, so that the entire current may pass through thegenerator when the drill is not acting. The conductors? r constitute thedrill-circuit, and the conductors r W constitute the short or shuntcircuit." These circuitconnections may bevaried in various well- -knownways. i

Fig. 7 shows a modified oi'm of the appadriven positively in bothdirections, by electro-magnetism and the circuit-breaker is'actuateddirectly by the drill-stock. We disclaim, broadly, these features, asthey are shown in an application, No. 8,370, forLetters Patent oftheUnited States, 1 filed by Charles E. Ball, April 26,

We claim as our own invention 1. The combination, substantially asherein set forth, of the frame, the stock adjustable therein, the coilor helix mounted in the stock, the core reciprocating endwise throughthe coil, the drilling-tool carried by the core, and therecoil-spring. T

'2. The combination,substantially as herein set forth, of the frame,thestock adjustable therein,

coil, the drilling-tool carried recoil-spring, thegenerator, thecircuit-connections, and the automatic circuit-breaker.

3. The combination, substantially as herein frame, the stock adjustablethe core reciprocating endwise through the coil, the drilling-toolcarried by the core, the and automatic feedingmechanism,substantiallysuch-as described, automati recoil-spring,

cally to regulate the feed according ,to the depth of penetration of thedrill'at each stroke.

This diagram shows one drill only I the coil or helix mounted in thestock, the core reciprocating endwise through the by the core, the

polygonal rod, constituting a prolongation of the core, its conicalhead, the feed Wheel through which the rod reciprocates and with whichit turns, and the feed-pawl actuated by therodintermittently to rotatethe wheel.

' 6. The combination, substantially as herein set forth, of the frame,the stock adjustable therein, the core, .the drillingtool carriedthereby, the polygonal rod projecting from the'core, the feed-wheelthrough which it"re-.

ciprocates andwith which it rotates, the

screw-wheel gearing with thefeed-wheel, and the feed-screw passingtherethrough.

7. The combination, substantially as herein set forth, of the frame, thestock adjust-able therein,*the coil or helix mounted in the stock,

the core reciprocating endwise throughthe coil, thedrilling-toolcarried'by the core, the

polygonalrod, constituting an extension thereof, the feed-Wheel throughwhich it passes and with which it turns, automatic nechan-* ism,substantially such as described, forintermittently rotatingv the feed-whel, ,thefl screw-wheel gearing with the feed-wheel, the

screw; passing therethrough, andja pawl or;

other suitable detent for' locking the screw while the drillisautomatically being fed'forward, but which allows'thescre'w to be lip"tated to retractthe drill; V r

- 8. ,Thecombiu'ation, substantially as herein set forth ,-of thestock,the coil mounted thereinjthe core reciprocating endw-ise through thecoil, the drill stock attached the .core,and the recoil -spring mountedon the tool-stock. Y i

roe

9. T The combination, substantially as herein I set'forth, of the.generator, the; electricdrill,

and thecircuit-connections oftheautomatic pendulum circuit breaker, thecircuit of r to which is closed bythe attraction of the mag net andbroken bythe recoilof the-spri 11g-- arm carrying the pendulum,

JIn testimony whereof We have hereunto set our hands thisf22d'dayof May,A; D; '1880, I

' ALFRED G. HOLCOMBE'.

. OHAS. A. OHEEV ER. Witnessesr 1 JOHN D.-S HED ocK, Q 1. g DwWn LI Ms.

